Relay control system



June 21, 1949. c. M. HINES 2,473,683

RELAY coN'rRoL SYSTEM Original Filed April :50," 1942 2 Shets-Sheet 1Fig.1

Iv (1X 2| -20a 2%. 759 Q w' @1 INVENTOR gLaudeM Himes ATTORNEY June 21,.1949. g, M, HlNEs 2,473,683

' RELAY GONTROLSYSYTEM Original Filed April :50, 1942 2 Sheets-Sheet 2INVENTQR glaudeM Hines ATTORNEY Patented June 21, 1949 RELAY CONTROLSYSTEM Claude M. Hines, Verona, Pa., assignor to The Westinghouse AirBrake Company, Wilmerding, Pa., a corporation of Pennsylvania Originalapplication April 30, 1942, Serial No. 441,197. Divided and thisapplication June 23, 1945, Serial No. 601,104

7 Claims.

This invention relates to control systems and particularly to controlsystems for selectively providing difierent characteristic controlimpulses for any desired purpose, the present application being adivision of my prior application, Serial No. 441,197, filed April 30,1942, now Patent No. 2,396,422, issued March 12, 1946, and assigned tothe 'assignee of the present application.

In my aforesaid prior application Serial No. 441,197 I have disclosedcontrol systems designed and employed for the control of signal devices,such as air raid warning signal devices. In the present applicationcontrol systems identical to those disclosed in my prior applicationSerial No. 441,197 are disclosed, but the subject matter of inventionclaimed in the present application is the novel control apparatus forproducing control impulses, which apparatus is of general utility insituations other than the control of si nal devices.

It is an object of my present invention to provide a control systemcharacterizedby novel coding and timing apparatus.

It is another object'of my present invention to provide a control systemincluding momentarily operable means for initiating a predeterminedcycle of control impulses.

It is a further object of my present invention to provide a controlsystem of a character indicated in the foregoing objects, and furthercharacterized by a novel arrangement including electrical relays wherebyto provide control impulses according to a selected code.

--The above objects and other objects of my invention which will be madeapparent hereinafter are attained byapparatus subsequently to bedescribed and shown in the accompanying drawings,

wherein Fig. 1 is a diagrammatic view showing a control system embodyingmy invention.

Fig. 2 is a development view of the commutator which is a part of thecoding apparatus disclosed in Fig. 1,

Fig. 3 is an end view of the coding and timing apparatus shown in Fig.1, showing further details of construction,

Fig. 4 is a fragmental enlarged sectional view taken on the line 4-1! ofFig. 3, showing further details of construction,

Fig. 5 is a fragmental diagrammatic view, showing a-modification of thecontrol system of a Fig. Bis a diagrammatic view, showing anotherembodiment of-my invention including a different type of coding andtiming'apparatus, and

2 Fig. 7 is a diagrammatic view, showing a modification of theembodiment shown in Fig. 6.

Description of system shown in Fig. 1

The system shown in Fig. 1 comprises an audible signal device in theform of an air operated horn H a source of air under pressure such as areservoir 12 which is charged to a certain operating pressure such asone-hundred pounds per square inch, by a suitable air compressor notshown; a magnet valve device [3 for controlling the supply of air fromthe reservoir l2 to the horn II, a signal coding and timing device M forcontrolling the operation of the magnet valve device l3; an electricmotor l5 for operating the signal coding and timing device 14 andadditional control apparatus including two remotely controlled relays I6and I1, two additional relays l8 and [9, respectively, controlled by therelays l6 and I1, two push button switches 21 and 22, and two additionalswitches 20a and 20b. The equipment further includes a suitable sourceof directcurrent such as a storage battery 23, the positive and negativeterminals of which are respectively connected to tWo bus wires '24 and25, hereinafter respectively referred to as the positive bus Wire andthe negative bus wire.

Considering the parts of the equipment in greater detail, the airoperated horn I I may be of the type shown in Patent 2,263,342 to NormanF. Lewis, in which the vibration of a sound-producing diaphragm isefiected in response to the continuous supply of air under pressure tothe horn. The particular construction of the horn II is, however, notmaterial to my invention inasmuch as any horn device operated inresponse to the. supply of air under pressure thereto may be employed.

The magnet valve device I3 may be any standard type. As diagrammaticallyshown, it may comprise a suitable casing having a chamber 21 to whichthe reservoir 12 is constantly connected by a pipe 28, a chamber 29 toWhich the horn H is constantly connected by the pipe 3 I, a valve 92 ofthe poppet type controlling communication between the chambers 21 and29, and a magnet winding 33 for operating the valve 32.

The valve 32 is normally urged upwardly to a seated position, closingcommunication between the chambers 28 and 29, by a coil spring 34 andunseated downwardly in response to energization of the magnet winding 33by means of a suitable plunger 35 actuated by the magnet winding.

It will thus be seen that when the magnet winding 33 is deenergized, thesupply of air to the horn H is cut off and the horn is silent. It willalso be seen that whenever and as long as the magnet winding 33 isenergized air under pressure is supplied to the horn to cause it toproduce an audible signal or blast.

It is preferable to employ a horn which is not directionally selective.Obviously, if directionally selective horns are employed, then aplurality of horns each pointed in a different direction may beconnected, in multiple, to the pipe 3! The signal coding and timingdevice l4 comprises a rotary shaft 3'! suitably mounted for rotation ina supporting casing, not shown, and adapted to be rotated at a suitablespeed by the motor i5 through a speed reduction gear mechanism 38. Theshaft 3'! is effective upon rotation to cause operation of a codingswitch formed by a commutator 39 fixed on the shaft and two stationarilysupported insulated brushes 4i and 42 associated therewith. Thecommutator 39 may comprise a suitable disk of insulating materialcarrying on the outer periphery thereof a continuous contact ring 43from which a desired number of contact fingers 44 projects axially inregular spaced relation circumferentially. (See Fig. 2.) The surfaces ofthe contact ring 43 and contact fingers 44 are flush with the portion ofthe insulating disk between the respective contact fingers, therebyforming a smooth contact face for the commutator.

The brushes 4| and 42 are supported in insulated relation by a suitablebrush holder in such a manner that the brush 4| continuously engages thecontact ring 43 and the brush 42 engages the contact fingers 44successively upon rotation of the commutator 3Q.

Brushes 4| and 42 are thus periodically connected and disconnected forsubstantially equal intervals of time, respectively, upon rotation ofthe commutator 39 at a constant speed.

The motor [5 is indicated as of the directcurrent shunt field type androtates at substantially constant speed in response to a predeterminedvoltage impressed thereon, thereby causing rotation of the shaft 31 at apredetermined selected speed. The speed of rotation of shaft 37 is suchthat the commutator 39 completes one full revolution in a certain lengthof time, such as two minutes.

The brushes 4| and 42 are thus connected and disconnected alternatelyfor predetermined and substantially equal intervals of time, the lengthof which depends upon the number of contact fingers 4'4 and thecorresponding number of insulating segments between the commutatorfingers '44. Thus, as shown in Fig. 2, the commutator 39 has sixteencontact fingers 3'4 and a corresponding number of insulating segmentsbetween the contact fingers. Assuming a complete revolution of the shaft31 and commutator 39 in two minutes, it will be seen that the brushes 4|and 42 are connected and disconnected alternately for approximatelythree and threequarters seconds.

It will be apparent that the width of the contact fingers 44 withrespect to the insulating segments between the contact fingers may bevaried so that the length of time that the brushes 4| and 42 areconnected with respect to the length of time that they are disconnectedmay correspondingly vary.

The coding and timing device 14 further comprises a timing switch deviceincluding a rotary cam disk 46 fixed on the shaft 31 and rotatabletherewith and two switches 41 and 48 of the 4 telephone type associatedtherewith and operated thereby.

Each of the switches 41 and 48 comprises a pair of contact fingershaving contacts which are normally biased into contact with each other,the contact fingers of the two switches being carried in insulatedrelation by a suitable support 5|. One of the contact fingers of theswitch 41 and a corresponding one of the contact fingers 48 are extendedand provided with a suitable insulating button 52 on the end thereofwhich slidably engages a corresponding face of the cam disk 46.

At one point adjacent the periphery of the cam disk 46 are two cams 53which are in axial alignment on opposite faces of the cam disk, as shownin Fig. 4. The cams 53 may be formed in a convenient manner by a singleelement in the form of a rivet extending through a suitable hole in thecam disk 46 and having the opposite ends suitably rounded to form thecams 53.

The earns 63 are located the same radial distance from the axis ofrotation of the shaft 31 as are the insulating buttons 62 on the contactfingers of the switches 41 and 48. It will thus be seen that as the camdisk 46 rotates through one certain position, the cams 53 engage theinsulating buttons 52 to bend the corresponding contact fingers of theswitches 41 and 46 out wardly from the corresponding faces of the camdisk to cause separation of the contacts carried by the contact fingers.After the cam disk 46 has passed through such certain position, thecontacts of the two switches 41 and 46 reenga'ge.

The cam disk 46 is fixed 0n the shaft 31 in such a manner as to causeopening of the switches 41 and 48 at a certain selected time in themanner hereinafter to be more fully explained.

The commutator 39 of the signal coding device |4 dilfers somewhat fromthat disclosed in the ccpending application Serial No. 441,196 of RobertA. Mitchell and Claude M. Hines, now Patent No. 2,381,224., issuedAugust 7, 1945, for the reason that in the present application thecommutator 39 is rotated continuously whereas, in the copendingapplication, the commutator is alternately moved and stopped while beingprogressively shifted rotatively.

The relays I6 and H are standard directcurrent relays of the neutraltype, each having a winding W and a single from; contact a. The windingsW of the relays l6 and 17 are connected by suitable wires to a remotecontrol station where they may be selectively energized and deenergizedby an operator. Such remote control station may be "a telephone exchangewhere an operator is always on duty.

The relays l8 and I! are standard direct current relays of the neutraltype. Relay II has a winding W, two front contacts a and b, and atransfer contact 0. Relay l9 has a winding W and three front contacts a,b, and 0, respectively.

It will be understood that the term front con tact refers to a contactwhich is in open position when dropped-out and in closed position whenpicked-up while the term trans'fer" contact refers to a contact which isin one closed position when dropped-out and a different closed positionwhen picked-up.

The push button switches 'll end in may he of any standard typerequiring the application of manual pressure to close them and to mammalthem closed, and being automatically W upon the release of manualpressure.

aszae a The switches a and 20b may be of any singlepole, single-throwtype, such as a knife switch or a snap switch of the rotary type. Theseswitches will be hereinafter referred to as cutout switches because theyare effective, when opened, to out the relays I6 and I1 out of operationin the manner hereinafter to be pointed out.

Operation of system shown in Fig. 1

Let it be assumed that the operator at the remote control stationdesires to cause the horn I I to Signal an air raid. To do so, heoperates a switch (not shown) at the remote control station, therebycausing energization of the magnet winding W of the relay It for a shortinterval of time.

The contact a of the relay I8 is accordingly actuated to its picked-upor closed position and is effective in such position to establish acircuit for energizing the winding W of the relay I8. This circuitextends from the positive bus wire 24 by way of a branch wire 51,another wire 58, contact a of the relay I6, and a wire 59, including inseries relation therein the cut-out switch Zila and the winding W of therelay I8, to the negative bus wire 25.

The contacts of the relay I8 are accordingly actuated to their picked-upposition. The contact b of the relay I8 is effective in its picked-up orclosed position to establish a self-holding circuit for the Winding ofthe relay l8. This circuit extends from the positive bus wire 24 by wayof the branch wire 51, a wire BI including in series relation thereinthe contact b of the relay I8 and the switch 41 of the signal coding andtiming device I4 to the wire 59, and thence through the winding W of therelay I8 to the negative bus wire 25.

It will thus be seen that once the relay I8 is picked-up it holds itselfpicked-up thereafter, thereby permitting the contact of the relay IE tobe restored to its dropped-out position. In other words momentarypick-up of the relay I6 causes the relay I8 to be picked-up andmaintained picked-up thereafter until the happening of an eventsubsequently to be described.

The contact a of the relay I8 is eifective in its picked-up or closedposition to establish a circuit for energizing the motor I5. Thiscircuit extends from the positive bus wire 24 by way of the branch wire51, a wire 62 including in series relation therein the contact a of therelay I8 and the parallel-connected armature and field windings of motorI5, to the negative bus wire 25 The motor I5 is accordingly rotated tocause rotation of the shaft 31 of the signal codin and timing device ata substantially constant speed.

The contact 0 of the relay I8 is eifective in its picked-up position toestablish a circuit for energizing the magnet winding 33 of the magnetvalve device I3. This circuit extends from the positive bus wire 24 byway of the wire 51, contact 0 of the relay I8 in its picked-up position,a wire 64' including in series relation therein the signal codingswitch, formed by the brushes 4| and 42 and the commutator 39, and themagnet winding 33 of the magnet valve device I3, to the negative buswire 25.

It will thus be seen that the magnet valve de vice I3 is periodicallyoperated to cause air under pressure to be supplied from the reservoirI2 to the horn I I as the commutator 38 of the signal coding and timingdevice I4 continues to rotate. The horn II accordingly is operated toemit an audible blast or signal periodically for alength of timecorresponding to the length of time that the brushes 4| and 42 areconnected by the commutator 39. As previously explained, the brushes 4|and 42 are alternately connected and disconnected for substantiallyequal lengths of time of approximately three and three-quarters seconds.Thus the audible signals produced by the horn II are separated by silentintervals of substantially the same duration.

The horn I I continues to operate to produce the coded signal,indicative of an air raid, in the manner just described as long as therelay I8 remains picked-up. The relay I8 is restored to its dropped-outposition due to the interruption of the self-holding circuit thereof inresponse to the opening of the switch 41 of the signal coding and timingdevice I4. The cam disk 46 is normally so positioned with respect to theswitches 47 and 48 that the shaft 37 rotates 7 through substantially afull revolution before the cams 53 on the cam disk 46 engage theinsulating buttons 52 on the contact fingers of the switches 51 and 43to cause opening of the switches. Accordingly, it will be seen that therelay I8 is not restored to its dropped-out position until the shaft 37completes substantially one full revolution following the initialpick-up of the relay I8, thus automatically timing the duration of thesignal sequence.

Upon restoration of the contact a of the relay I 8 to its dropped-out oropen position, the circuit previously traced for energizing the armatureand field windings of the motor I5 is interrupted. Due to the inertia ofthe motor armature and the other rotating parts rotated thereby themotor armature rotates suiiiciently long, after interruption of theenergizing circuit in response to the restoration of the relay I 8 toits dropped-out position, to insure the cams 53 on the cam disk 46passing the switches 41 and 48 so as to reclose the switches before theshaft 3! is stopped. Obviously, once the contact b of the relay IB isrestored to its dropped-out or open position, the reclosure of theswitch 41 is ineffective to restore the self-holding circuit for thewinding of the relay IB and consequently the relay I8 remains in itsdropped-out position thereafter unless again picked-up in the mannerpreviously described by operation of the relay I6 or by means of thepush button switch 2I in the manner presently described.

If the local operator desires to cause operation of the horn II toproduce the coded signal indicative of an air raid he may do so merelyby momentarily closing the push button switch 2I. The switch 2| isconnected in parallel with the contact a of the remotely controlledrelay I6 and accordingly is effective upon closure to cause pick-up ofthe relay I8 in the same manner as if the relay I6 is picked-up.

The operation of the equipment to produce a periodic blast of the horn II for a predetermined time is thus effected in the same manner aspreviously described and the description accordingly is not repeated.

If the local operator for any reason desires to cut the remotelycontrolled relay I6 out of operation he may do so merely by opening thecutout switch 26a. The switch 20a, being in series with the contact a ofthe relay I6 and the Winding of the relay I8, is effective when openedto render the pick-up of the relay I6 ineffective to cause pick-up ofthe relay I8.

Now let it be supposed that the operator at the remote control stationdesires to cause operation of the horn H to produce the all clearsignal. To do so, he closes a switch for causing energize,- tion of thewinding W of the relay [1, the contact a of which is accordinglyactuated to its picked-up or closed position. The contact a of the relayl! is effective in its picked-up position to cause energization of thewinding N of the relay l9, This circuit extends from the positive buswire 24 by way of the wires 5! and 58, contact a of the relay I1, and awire 65 including in series relation therein the cut-out switch 20?) andthe winding W of the relay E9 to the negative bus wire 25. The contactsof the relay l9 are accordingly actuated to their respective picked-upor closed positions.

The contact oi the relay I9 is effective in its picked-up or closedposition to establish a selfholding circuit for the winding W of therelay I9, thus permitting restoration of the contact of the relay I! toits dropped-out position once the relay I9 is picked-up. Thisself-holding circuit for the winding of the relay l extends from. thepositive bus Wire 24 by way of the Wire 51, contact c of relay 18 in itsdropped-out or closed position, and a wire 69 including in seriesrelation therein contact 0 of the relay i9 and switch 48 of the signalcoding and timing device It to the wire 65, and thence through thewinding VI of the relay Is to the negative bus wire 25.

The contact a of the relay i9 is connected in parallel with contact a ofthe relay IS and is therefore effective, in its picked-up position, tocause energization of the armature winding and field winding of themotor If: in the same manner as does the contact a of the relay 58.Accordingly, the motor l5 starts to rotate the shaft 37 the instant therelay 5!! is picked-up and continues to rotate it until such time as therelay i9 is restored to its dropped-out position in the manner presentlyto be described.

The contact b of the relay i9 is eifective in its picked-up position tocause energization of the winding 33 of the magnet valve device 13independently of the coding switch including the brushes 4! and 42 andcommutator 39 of the coding and timing device it. This circuit extendsfrom the positive bus wire 24 by way of the wire 51, a wire l'l havingin series relation therein contact b of the relay [9 to the wire 64 at apoint "I2 between the brush 52 and the winding 33 of the magnet valvedevice [3, thence by way of the wire 64 and winding 33 of the magnetvalve device 13 to the negative bus Wire 25.

It will thus be seen that although the shaft 3'! continues to rotate,the signal coding switch formed by the brushes 4i and 42 and thecommutator 39 is inefiective to control the magnet winding 33 of themagnet valve device 13, because in this instance it is controlleddirectly by the contact I: of the relay I9.

Upon the pick-up of the relay l 3, therefore, the magnet winding of themagnet valve device I3 is energized and the magnet valve device l3accordingly operated to cause air under pressure to be supplied tooperate the horn H continuously until such time as the relay is isrestored to its dropped-out position.

The horn H accordingly operates to produce a continuous audible signalor blast, indicative of the all clear signal, until such time as the camdisk 46 of the coding and timing device it completes a full revolutionfrom the time the relay 19 was initially picked-up. At the expiration ofthe time required for a full revolution of the cam. disk 46, the switch"is opened momen- 8 tarily in the manner previously described for theswitch 41, thereby interrupting the self-holding circuit for thewindingof the relay l9 and causing the contacts of this relay to be restored todropped-out position.

Upon the restoration of the contacts of the relay I! to theirdropped-out positions, the magnet winding 33 of the magnet valve device[3 is deenergized, as is the armature winding and field winding of themotor l5. Accordingly, the supply of air to the horn H is cut-off andthe audible signal produced thereby is terminated. At the same time, themotor l5 coasts to a stop promptly, in the manner previously described,so as to cause reclosure of the switch 4-8. Reclosul'e oi the switch 48renders the self-holding circuit for the winding of the relay l9potentially effective again subject to subsequent pick-up of the relayit.

If the local operator desires to cause operation of the horn l I toproduce a continuous blast indicative of the all clear signal, he may doso by momentarily closing the push button switch 22. The push buttonswitch 22 is connected in parallel to the contact a or the relay I1 andconsequently the momentary closure of the switch 22 operates in the samemanner as if the relay ll were picked-up. Accordingly, it is deemedunnecessary to describe the operation of the equipment in response tothe closure of the switch 22.

If for any reason the local operator desires to cut the remotelycontrolled relay l1 out of operation, he may do so merely by opening thecutout switch 20b. The cut-out switch Zfib is connected in series withthe contact a of the relay H and the winding of the relay l9 and isthere fore eifective in its open position to prevent the energization ofthe winding of the relay 19 by pick-up of the contact of the relay ll.At the same time, the opening of the cut-out switch 20b does not preventpick-up of the relay [9 by operation of the push button switch 22.

Modification shown in Figure 5 Referring to Fig. 5, a modification ofthe equipment shown in Fig. 1 is disclosed in which an electricallyoperated horn 1 IA is employed rather than the air operated horn H. Insuch case, the reservoir [2 is unnecessary and is therefore dispensedwith. The equipment of Fig. 5 is thus substantially identical with thatin Fig. 1 except that the electroresponsive element in the horn HA issubstituted for the magnet winding 33 of the magnet valve device 13 inthe circuit including the wire 64 controlled either by the signal codingswitch device M or contact b of the relay Description of system shown inFigure 6 The air raid warning system shown in Fig. 6 is similar to thatin Fig. 1 in that it comprises an air operated horn H, a source of airunder pressure including the reservoir l2 and a magnet valve device l3asimilar to magnet valve device l3, for controlling the supply of airunder pressure from the reservoir l2 to the horn II.

In other respects the system shown in Fig. 6 is substantially differentfrom that in Fig. 1. The apparatus for controlling the operation of thehorn II to produce a coded signal indicative of air raid" or all clearcomprises two coding relays 15 and I6 respectively, with which areassociated two electrical condensers l1 and 18 respectively; two controlrelays l9 and and two push button switches 8| and 82.

The apparatus for timing the duration of a coded signal sequencecomprises a pneumatic timing switch device 85; a magnet valve device 86controlling the operation of the timing switch 85; and a choke device 81for controlling the rate of flow of air under pressure from thereservoir I2 to the timing switch 85.

Relays I5 and I6 may be of the direct-current neutral type. Each ofthese relays has a wind ing W, a front contact a and a back contact 19.The front contact of each relay is in open position when the winding ofthe relay is deenergized and is actuated to the picked-up or closedposition when the winding of the relay is energized. The back contact I)of each relay is closed in the dropped-out position and is actuated tothe pickedup or open position in response to energization of the windingof the relay.

The control relays I9 and 80 are identical, each having two operatingwindings a and b, and'three front contacts c, d, and e, respectively.

The winding a of each of the relays is connected in a suitable circuitto a remote control station, such as a telephone exchange, and iseffective when energized to cause pick-up of the contacts of the relay.

The winding b of each of the relays I9 and 86 is a self-holding andpick-up winding effective when energized to either pick-up the contactsof the relay or maintain them picked-up if already actuated to thepicked-up position.

When the contact 0 of each of the relays I9 and 80 is actuated to itspicked-up or closed position, it establishes a self-holding circuit forthe winding b of the corresponding relay which circuit extends from thepositive bus wire 24 through the series-connected contact 0 of the relayand the corresponding winding 1) of the relay to the negative bus wire25.

The push button switches 8| and 82 correspond to the push buttonswitches 2| and 22 of Fig. 1 and are connected in parallel relation tothe contact 0 of the relays I9 and 80 respectively. It will accordinglybe seen that closure of the switches 8I and 82 causes energization ofthe winding b of the corresponding relays 'I9 and 86 to cause pick-upthereof, the winding 1) being thereafter maintained energized due to theclosure of the corresponding contact 0 notwithstanding the subsequentopening of the switch 8| or 82.

The timing switch device 85, as diagrammatically shown, comprises amovable contact m and two cooperating stationary insulated contacts s.The switch formed by the movable contact m and stationary contacts scontrols connection of the positive bus Wire 24 to the positive terminalof the battery 23. As shown, the movable contact m is carried ininsulated relation on a stem 89 of a piston 9I that operates in the bore92 of a suitable casing member 93. A coil spring 90 interposed betweenone face of the piston 9| andthe closed end of the casing 93 yieldingurges the piston 9I into seated relation on an annular rib seat 94surrounding a port 95 that opens into a suitable chamber or volumereservoir 96.

In the seated position of the piston 9I, the movable contact m engagesthe stationary contacts s, thereby connecting the positive bus wire 24to the positive terminal of the battery 23.

Upon the supply of air under pressure to the volume reservoir 96 at aselected rate, in the manner presently to be described, a certain lengthof time is required to build-up sufficient pressure on the inner seatedarea of the piston 9I to overcome the force of the spring 96. When thepiston 9I is unseated from the annular rib seat 94, the increased areaof the piston 9i subject to the air pressure in the volume reservoir 66causes the piston to be snapped suddenly upward to a limiting positiondetermined by engagement with a boss 91 within the casing 93, therebycausing the movable contact m to be suddenly disengaged from thestationary contacts s, that is, operated to open position.

A port 99 in the casing 93serves to prevent dash-pot action of thepiston 9I and the consequent delay in the opening of the switch.

The magnet valve device 86 controls the supply of air from the reservoirI2 to. the volume reservoir 96. As shown, the magnet valve device itcomprises two oppositely seating poppet valves IUI and I02 operated inone direction to unseated and seated positionsrespectively by a coilspring I63 and in the opposite direction to seated and unseatedpositions in response to energizatien of a magnet winding or solenoidI94.

The valve IUI is contained in a chamber tilt that is constantly open toatmosphere through an exhaust port I66 and its fluted stem extendsthrough a suitable bore into a chamber Iill that is constantly connectedby a pipe I66 to the volume reservoir 96.

The valve I62 is contained in a chamber 569 that is connected by a pipeI I9 and a branch pipe I I I to the reservoir I2, the choke device 8?being interposed in the pipe H6 between the III and the chamber I99. Thefluted stem of the valve I02 extends through a suitable port into thechamber I 81 and engages the end of the fluted stem of the valve ml inend-to-end relation.

It will thus be apparent that when the winding I04 of the magnet valvedevice 86 is deenergized, the. air under pressure in volume reservoir 96is exhausted to atmosphere through the exhaust port I66 in the magnetvalve device. It will also be apparent that when the magnet winding I84of the magnet valve device 66 is energized, the exhaust communicationjust described is closed, due to seating of the valve Nil, and a supplycommunication is opened due to the unseating of the valve I62 throughwhich air under pressure is supplied from the reservoir I2 to the volumereservoir 96 at the controlled rate determined by the flow area of thechoke device 81.

As previously indicated, the rate 0i": supply of air under pressure tothe volume reservoir is so controlled by the choke device 81 that acertain length of time, such as two minutes, is required. in order tobuild-up a suflicient pressure within the chamber 96 to cause upwardunseating movement of the piston and the consequent opening of thecontacts of the switch device 85.

Operation of system shown in Figure 6 Let it be assumed that theoperator at the re mote control station desires to cause operation ofthe horn II to produce a coded air raid signal, and that he accordinglycauses the winding a of the control relay I9 to be energized.

The contacts of relay I9 are accordingly actuated to their respectivepicked-up or closed positions in which the contact 0 is effective to establish the self-holding circuit of the winding b of the relay I9 in themanner previously indi cated. The contacts of relay I9 accordinglyremain picked-up notwithstanding the deenergization of the winding a ofthe relay 19, until such 11 time as the self-holding circuit for thewinding b of the relay [9 is interrupted in the manner hereinafter to bedescribed.

The contact (1 of the relay I9 is efiective in its picked-up or closedposition to establish a circuit for energizing the magnet winding I04 ofthe magnet valve device 85. This circuit extends from the positive buswire 24 by way of a branch wire H5, a wire H6 including in seriesrelation therein contact d of relay l9- and the winding I04 of themagnet valve device 86 to a wire I I1 which is, in turn, connected tothe negative bus wire 25.

The magnet valve device 86 is accordingly operated to cause air underpressure to be supplied at a controlled rate from the reservoir I2 tothe volume reservoir 96, thereby to cause opening of the timing switch85 at the expiration of a certain length of time, such as two minutes.

The contact e of the relay [9 is effective in its picked-up or closedposition to establish a circuit for energizing the winding of the relayl6 and for charging the condenser I8. This circuit extends from positivebus wire 24 by way of the branch wire H5, contact a of relay 19, a wireI I8 including the back contact b of relay 15, through theparallel-connected winding W of relay It and the condenser 18 to a wireI I9 that is connected to the negative bus wire 25.

The condenser 18 is accordingly charged to a voltage corresponding tothe battery voltage impressed on the bus wires 24 and 25' and thecontacts of the relay [8 are, at substantially the same time actuated totheir respective pickedup positions.

The contact a of the relay 16 is effective in its picked-up or closedposition to establish a circuit for energizing the winding W of therelay 15 and for charging the condenser TI. This circuit extends fromthe positive bus wire 24 by way of 1 a branch wire I2I, a second branchwire I22 mcluding the contact a of the relay [6, the parallel connectedwinding W of relay I and condenser 11, and a wire I123 to the negativebus wire 25. The condenser 11 is accordingly charged to the voltageimpressed on the bus wires 24 and 25 and the contacts of the relay 15are substantially simultaneously actuated to their respective picked-uppositions.

The back contact I) of relay 15 is effective in its picked-up positionto open the circuit for energizing the winding W of the relay T6 and forcharging the condenser 18. The contacts of the relay [6 are not,however, restored at once to their dropped-out position because thecondenser 18 discharges current locally through the winding W of therelay 16, thereby holding the contacts of the relay in their picked-uppositions for a certain length of time, such as two or three seconds.

Upon the restoration of the contacts of the relay 16 to theirdropped-out position, a circuit is established for energizing thewinding 33 of the magnet valve device I3a. This circuit extends from thepositive bus wire 24 by way of the wire I2I, serially-connected contactI) of relay [6 and contact a of relay 15, a Wire I25, the magnet winding33 of the magnet valve device l3a, and wire I I! to the negative buswire 25.

The magnet valve device I3a is accordingly operated to cause air underpressure to be supplied from the reservoir l2 to the horn II to causethe horn to produce an audible signal or blast during the time that aircontinues to be supplied to the horn.

Contact a of relay 16 is effective when restored toits dropped-out oropen position to interrupt the circuit for energizing the winding W ofthe relay l5 and for charging the condenser ll. Like the relay '15, therelay i5 is not immediately restored to its dropped-out position but ismaintained picked-up by the current discharged lo cally from thecondenser 11 through the winding of the relay 15. After a certaininterval of time, such as two or three seconds, the current dischargedfrom the condenser TI through the winding of the relay I5 diminishessuiiiciently to cause restoration of the contacts of the relay '15 totheir dropped-out position.

Restoration of the contact a of relay 15 to its dropped-out or openposition interrupts the circuit for energizing the magnet winding 33 ofthe magnet valve device I3a. The magnet valve de-- vice I30: isaccordingly operated to cut-oil": the supply of air under pressure tothe horn H and the signal produced by the horn is thus terminated.

The contact I) of relay 15 is efifectiye when restored to itsdropped-out or closed position to reestablish the circuit for energizingthe winding of relay It and for charging the condenser 13. The contactsof relay 16 are accordingly pickedup and the condenser 18 is charged.Pick-up of the relay 15 causes energization of the, winding of the relay'!5 and charging of the condenser T1 in the manner previously described.Pick-up of the contacts of the relay 15 interrupts the circuit forenergizing the winding of the relay l6 and for charging the condenser18. After a certain length of time, such as two or three seconds, thecontacts of relay 16 are again restored to their dropped-out position inwhich the circuit for energizing the magnet winding 33 of the magnetvalve device [3a is again established in the manner previouslydescribed.

It will thus be apparent that the coding relays l5 and 76 continue to bealternately picked-up and dropped-out, in the manner previously described to cause the magnet winding of the magnet valve device lSa to bealternately energized and deenergized for approximately the same lengthof time, namely two or three seconds, thereby causing the horn II to beperiodically operated to produce audible signals of two or three secondsduration as long as the control relay 19 remains picked-up. v

The control relay 19 remains picked-up until such time as theself-holding circuit for the winding 2) thereof is interrupted due tothe opening of the timing switch 85. As previously explained, the timingswitch is opened upon the expiration of a certain length of time, suchas two minutes, following the initial energization of the magnet windingI04 of the magnet valve device 86 which occurs in response to theinitial pick-up of the control relay 19.

Upon the restoration of the control relay I?! to its dropped-outposition, operation of the coding relays I5 and 16 is terminated due tothe interruption of the circuit including the contact 6 of the relay 'i9Consequently, with the two coding relays l5 and 16 in their respectivedropped-out positions, the circuit for energizing the magnet winding ofthe magnet valve device I3a is interrupted and remains interrupted atthe contact a of the relay 15. 1

The restoration of the contact d of the relay T9 to its dropped-out oropen position interrupts the circuit for energizing the magnet windingI04 of the magnet valve device 86. The magnet valve device 86 isaccordingly operated to the position shown in the drawing in which thesupply of air under pressure from the reservoir I2 to the volumereservoir 96 is terminated and the air under pressure in the volumereservoir 96 is exhausted to atmosphere through the exhaust port IE6 ofthe magnet valve device 86.

Upon the sufiicient exhaust of air under pressure from the volumereservoir 96, the spring 90 returns the piston 9I downwardly into seatedposition on the annular rib seat 94, thereby reengaging the contacts ofthe timing switch 85. It will be apparent that the reclosing of thetiming switch E5 is not effective to cause the relay T9 to be againpicked-up because the contact of the relay '19 has been previouslyrestored to its dropped-out or open position.

If the local operator desires to cause operation of the horn I I toproduce a coded air raid signal, he may do so merely by momentarilyclosing the push buttom switch 8i, thereby energiz: ing the winding 2)of the relay I9 and causing the contacts of the relay to be actuated totheir picked-up position, in which the contact 0 is effective toestablish the self-holding circuit for the winding 12 of the relay.Thereafter the push button switch 8! may be opened and the relay I9remains in its picked-up position.

In view of the fact that the operation of the system is the same aspreviously described once the relay I9 is picked-up, it is not necessaryto repeat a description of such operation.

Let it now be supposed that the operator at the remote control stationdesires to cause operation or the horn II to produce an all clearsignal.

To do so he causes the winding a of the control relay 80 to be energizedand the contacts of the relay accordingly actuated to the picked-upposition. The self-holding circuit for the winding 1) of relay 80 isaccordingly established by contact 0 of relay 80 in its picked-up orclosed position, and thereafter the winding a of the relay 89 may bedeenergized without causing the contacts of the relay to be restored totheir dropped-out position.

The contact 11 of the relay 80 is effective in its picked-up or closedposition to establish a circuit for energizing the magnet winding I M ofthe magnet valve device 86. This circuit extends from the positive buswire 24 by way of the branch wire I2I, contact d of the relay 80, wireII'IS, magnet winding I04 of magnet valve device 86, and wire II! to thenegative bus wire 25. The magnet valve device 86 is accordingly operatedto cause air under pressure to be supplied at a rate controlled by chokedevice 81' from the reservoir I2 to the volume reservoir 96 as long asthe relay 80 remains picked-up.

The contact 6 of the relay 80 is effective in its picked-up or closedposition to establish a circuit for energizing the winding of the relayI and charging the condenser IT. This circuit extends from the positivebus Wire 24 b way of the branch wire IZI, a wire I21 including thecontact e of the relay BI], wire I22, the parallel connected winding Wof relay l5 and condenser 11, and wir I 23 to the negative bus wire 25.The condenser I! is accordingly charged and the contacts of the relay I5are actuated to their picked" up position.

The contact a of the relay I5 is efiective in its picked-up or closedposition to establish the circuit for energizing the magnet winding 33of the magnet valve device i3a, which circuit has been previouslytraced. The magnet valve I3a is accordingly operated to cause air underpressure to be supplied from the reservoir I2 to the horn II to cause itto operate to produce its audible signal.

In this instance, however, the relay I6 remains in its dropped-outposition and the relay 15 remains in its picked-up position as long asthe relay 89 remains in its picked-up position. Accordingly, the magnetvalve device IZ-la causes air under pressure to be supplied continuouslyto the horn I I until such time as the rela Iii) is restored to itsdropped-out position as a result of the interruption of the se1f-holdingcircuit of the winding 12 of relay 89 due to the opening of the timingswitch 85.

As in the case of an air raid signal, the timing switch 85 is actuatedto its open position at the expiration of a certain time, such as twominutes, following the initial pick-up of the relay 3!). It willaccordingly be seen that the horn I I continues to produce a continuousaudible signal. for a predetermined length of time, such as two minutes,to indicate the all clear signal.

Upon the interruption of the self-holding cir-- cuit for the winding bof relay 89 due to the opening of the timing switch 85, th contacts ofthe relay are restored to their dropped-out position. The contact dofrelay 89 is effective in its dropped-out or open position to interruptthe circuit for energizing the magnet winding IM of the magnet valvedevice 35. Magnet valve device 86 is thus operated to cut-ofi the supplyof air under pressure to the volume reservoir 96 and to cause air underpressure to be xhausted from the volume reservoir 9% to atmospherethrough the exhaust port Ififi. Upon sufficient reduction of thepressure in the volume reservoir 96, the timing switch is restored toits closed position.

Contact 6 of the relay 89 is effective in its dropped-out position tointerrupt the circuit for engerizin the winding W of the relay l5. Aftera certain length of time, such as two or three seconds, during which thecondenser 'Il dis charges current through the winding of the relay I5,the contacts of the relay it are restored to their dropped-out position.The restoration of the contact a of the relay 7:; to its dropped-out oropen position interrupts the circuit for energizing the magnet winding33 of the magnet valve device I3a. The magnet valve device lad is thusoperated to cut-off the suppl of air under pres sure from the reservoir52 to the horn II which accordingly ceases to produce the audiblesignal.

If the local operator desires to cause operation of the horn II toproduce the all clear signal, he may do so merely by momentarily closingthe push button switch 92. Momentary closure of the switch 92 causespick-up of the relay 80 which is accordingly stuck-up thereafter by theselfholding circuit of the relay. Operation of the system is thereafterthe same as that, previously described, initiated by an operator at aremote control station and is accordingly not repeated.

System shown in Figure 7 The air raid warning system shown in Fig. 7 isfor the most part identical with that shown in Fig. 6, difieringtherefrom in the omission of the two coding relays Iii and lb and thetwo condensers I1 and I8 and the substitution therefor of a singlecoding relay 35A, an electrical condenser HA, and three adjustableresistors I3I, I32, and I33, respectively.

Those parts of the system shown in Fig. 7 which correspond identicallyto corresponding parts in the system shown in Fig. 6 are identified bythe same reference numerals without further description.

The coding relay 15A is of the direct-current neutral type having twoseparate windings a and 1), two front contacts and d, and a back contact 6.

Operation of system shown in Figure 7 Let it be assumed that theoperator at the re mote control station desires to cause operation ofthe horn II to produce an air raid signal and accordingly causes thewinding 0. of the relay 19 to be energized momentarily. Contact 0 of therelay I9 is efiective in its picked-up position to establish theself-holding circuit for the winding b of the relay 3'8 to maintain therelay pickedup notwithstanding subsequent deenergization of the winding11 of the relay Ill.

The contact at of the relay I9 is effective in its picked-up or closedposition to establish a circuit picked-up position to establish acircuit for energizing the winding a of the coding relay 15A and forcharging the condenser TIA. This circuit extends from the positive buswire 2' 3 by way or the branch wire H5, contact 6 of the relay IS, awire I35, back contact 6 of the coding relay 15A, resistor I3I, a Wire Ito the point I31 where the circuit divides into two parallel branches,one branch including the condenser 11A and the other branch includingthe resistor I32 and the winding a of the coding relay 75A, the twobranches rejoining at the point I38, thence by way of a wire I39 and awire IM to the negative bus wire 25.

The condenser "(1A is accordingly charged and the contacts of the relay15A actuated to their picked-up positions.

The back contact c of the relay 15A is effective in its picked-up oropen position to interrupt the energizing circuit for the winding a ofthe relay 15A and the charging circuit for the condenser HA. Thecontacts of the relay 15A are not immediately restored to theirdropped-out position, however, because the condenser 'IIA dischargescurrent locally through resistor I32 and winding a of the relay 15A aswell as through the winding 1; of the relay 15A and the resistor I33.

The contact 0 of the coding relay 15A is effective in its picked-upposition to establish the circuit including the winding 1) of the rela15A and the resistor I33 in the manner readil apparent in the drawing.

The resistors I32 and I33 may be adjusted in value to so control thecurrent discharged from condenser 'I'I'A to the respective windings aand b of the relay 15A as to vary the time that the contacts of therelay remain held in their pickedup position due to the currentdischarged from the condenser. They may be so adjusted, for example, asto cause the contacts of the relay 15A to remain in their picked-uppositions for at least three seconds following the pick-up of the relaycontacts.

The contact (1 of the relay 75A is effective in its picked-up or closedposition to establish a circuit for energizing the magnet winding 33 ofthe magnet valve device I3a. This circuit extends from the positive buswire 24 by way of the branch wire I2I, a wire I43 including the contactd of the relay 15A, magnet winding 33 of the magnet valve device I31:and the wire II! to the negative bus wire 25.

The magnet valve device I3a is accordingly operated as in the system ofFig. 6 to cause air under pressure to be supplied to the horn II tocause an audible signal to be produced as long as the magnet winding 33thereof is energized.

Upon the restoration of the contacts of the relay 15A to theirdropped-out position, contact e of relay 15A is effective to reestablishthe circuit for energizing the winding a of the relay 75A and forcharging the condenser 11A. The resistor I3I in the circuit, functionsto delay for a certain length of time such as two or three seconds thepick-up of the contacts of the relay. During this interval of time thecontact (1 of the relay 15A is in open position interrupting the circuitfor the magnet winding of the magnet valve device I3a. During suchinterval of time, the magnet valve device I3a accordingly cuts-off thesupply of air under pressure to horn II, thereby causing cessation ofthe audible signal.

When the contacts of the relay 15A are again picked-up, the circuit forenergizing the magnet winding of the magnet valve device I So is againestablished for the interval of time corresponding to the time'that thecontacts of the relay 15A remain held in their picked-up position by thecurrent discharged from the condenser "A.

It will thus be apparent that as long as the relay 1!! remainspicked-up, the coding relay 15A will be alternately picked-up anddropped-out to cause the magnet; valve device l3a to be operated in sucha manner as to alternately supply and cut-01f the supply of air to thehorn II, thereby causing the horn to produce periodic blasts insubstantially the same manner as in the system of Fig. 6.

Upon the expiration of a certain length of time, such as two minutes,the timing switch opens and accordingly interrupts, the self-holdingcircuit for winding 1) of the relay 19, thereby causing restoration ofthe contacts of the relay I9 to their dropped-out position.

The magnet winding of the magnet valve 86 is accordingly deenergized andthe magnet valve operated to terminate the further supply of air underpressure to the timing switch and to cause an exhaust of air underpressure. from the volume reservoir 96 whereby the timing switch 85 isrestored to its closed position,

At the same time, the restoration of the contact e of the relay I9 toits dropped-out or open position causes the coding relay 15A to ceasefurther operation and remain in its dropped-out position wherein thecircuit for energizing the magnet winding of the magnet valve device I3ais interrupted.

It will accordingly be seen that the system opcrates automatically inresponse to the pick-up of the relay I9 to cause operation of the hornII to produce periodic audible signals for a certain length of time,such as two minutes.

An air raid signal may also be initiated by a local operator momentarilyclosing the pick-up switch 8| just as in the system of Fig. 6,

If the operator at a remote control station desires to cause operationof the horn II to pro, duce the all clear signal, he may initiate such17 operation by causing momentary energization of the winding a of therelay 80. Once the contacts of the relay 8!! are actuated to theirpicked-up position the self-holding circuit for the winding b of therelayis established by the contact thereof as in the system of Fig. 6.

The contact d of the relay 8G is effective in its picked-up or closedposition to establish the circuit for energizing the magnet winding I04of the magnet valve device 66. The magnet valve device 85 is accordinglyoperated to cause air under pressure to be supplied from the reservoir12 to the volume chamber 96 of the timing switch 85 at a controlled ratedetermined by the choke device 81.

Contact e'of the relay 80 is effective in its picked-up or closedposition to establish a circuit for energizing the winding a of thecoding relay 75A as well as for charging the condenser NA.

This circuitextends from the positive bus wire '24 by way of the wireIZI, a branch wire MT includin the contact e of the relay 88 to the wirei% at the point I31, thence through the two parallel branches includingrespectively the condenser llA and resistor I32 and winding (1 of relay15A to the point I38, and thence by wires its and 14! to the negativebus wire 25.

The coding relay 15A is accordingly pickedup and maintained picked-up aslong as the relay so remains picked-up.

The magnet winding of the magnet valve device l3a is accordinglycontinuously energized as long as the relay 15A is picked-up to causeair under pressure to be supplied to the horn H by the magnet valvedevice l3a.

When-the timing switch 85 is opened at the expiration of a certain time,such as two minutes, following the initial pick-up of the relay 36 toeffect the interruption of the self-holding I circuit of the relay andthe consequent restoration of the contacts of the relay to theirdroppedout position, the circuit for energizing the magnet windings ofthe magnet valve devices 85 and iiia are accordingly interrupted andfurther operation of the horn terminated just as in the system of Fig.6.

lhe contacts of the relay 15A will be maintained picked-up for a certainshort interval of time, such as occurs during an air raid signal due tothe discharge of the current from the condenser "A through the windingsa and b of the relay following the restoration of the contact e of therelay 80 to its dropped-out or open position. Actually, therefore, thehorn H continues to produce an audible signal for a short interval oftime of the order of several seconds followin the drop-out of the relayBil.

The local operator may initiate an all clear signal operation of thehorn H merely by momentarily closing the push button switch 82, just asin the system of Fig. 6.

Summary Summarizing, it will be seen that I have disclosed severalembodiments of an air raid warning system, all of which areautomatically operative to cause any selected one of a plurality ofcoded signals to be produced by an audible signal device, such as an airoperated horn. All of the systems described, moreover, are effective tocause the signal device to operate to produce a selected coded signalfor a certain length of time, such as two minutes, in response to amomentary control impulse or operation.

In one embodiment, a combination coding and timing apparatus driven byan electric motor is provided.

In the other embodiments, a pneumatic timing switch mechanism isprovided which is set in operation in response to the initiatingmomentary control impulse for timing the duration. of the signalsequence. In one of the latter two embodiments, two cooperating codingrelays are provided effective to cause intermittent operation of thehorn. One of these relays is effective upon operation to produce acontinuous operation of the horn.

In the other of the last two mentioned embodiments, 9, single codingrelay is provided, which is alternately picked-up and dropped-out, atone time, to cause intermittent operation of the horn and which iscontinuously picked-up to cause continuous operation of the horn, atanother time, dependent upon the particular signal sele-cted.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a control system, the combination of two relays each of which hasa winding effective upon energization to cause pick-up of the relay,means associated with each of said relays for imparting a slow drop-outcharacteristic to said relay, means for causing energization of thewinding of one of said relays, means effective in response to pick-up ofsaid one relay for causing energization of the winding of the other ofsaid relays, means efiective in response to pick-up of said other relayfor effecting deenergization of the winding of said one relay, and meanscontrolled jointly by said two relays for effecting periodic controlimpulses.

2. In a control system, the combination of two relays each of which hasa winding effective upon energization to cause pick-up of the relay,means associated with each of said relays for imparting a slow drop-outcharacteristic to said relay, means for causing energization of thewinding of one of said relays, means effective in response to pick-up ofsaid one relay for causin energization of the winding of the other ofsaid relays, means effective in response to pick-up of said other relayfor effecting deenergization of the winding of said one relay, and meanscontrolled jointly by said two relays and efiective while said one relayis dropped-out and the said other relay is picked-up for producing acontrol impulse.

3. In acontrol system, the combination of two electrical relays each ofwhich has an operating winding, two electrical condensers one of whichis connected in parallel to the Winding of one of said relays and theother of which is connected in parallel to the winding of the other ofsaid relays, a circuit including the winding of said one relay, manuallycontrolled means for establishing said circuit to cause energization ofthe winding of said one relay and the pick-up of said relay, a circuitincluding the winding of said other relay, means efiective in responseto the pick-up of said one relay for establishing the last said circuitto cause energization of the winding and consequent pick-up of saidother relay, means effective in response to pick-up of said other relay,for interrupting the first said circuit including the winding of saidone relay, the condenser connected in parallel with the winding of eachof said relays being effective to discharge current locally through thewinding of the corre- 19 sponding relay to' maintain it picked up for acertain length of time following the interruption of the circuitincluding the Winding of the relay, and means controlled jointly by saidtwo relays for effecting periodic control impulses.

'4. In a control system, the combination of two electrical relays eachof which has an operating winding, two electrical condensers one 'ofwhich is connected in parallel to the Winding of one of said relays andthe other of which is connected in parallel to the winding of the otherof said relays, a circuit including the windings of said-one relay,manually controlled means for establishing said circuit to causeenergization of the winding of said one relay and the pick-up of saidrelay, a circuit including the winding of said other relay, meanseffective in response to the pick-up of said one relay for establishingthe last said circuit to cause 'energiza-tion of the winding andconsequent pick-up of said other relay, means effective in response topick-up of said other relay for interrupting the first said circuitincluding the winding of said one relay, the condenser connected inparallel with the winding of each of said relays being effective todischarge current locally through the winding of the corresponding relayto maintain it picked-up for a certain length of time following theinterruption of the circuit including the winding of the relay, andmeans controlled jointly by said two relays and effective control relayhaving a winding effective when,

energized to cause pick-up of the relay, means effective in response 'topick-up of said relay for causing energization of the winding of therelay in a manner to maintain said "relay picked-up, a pair of codingrelays each of which has an operating Winding, means associated witheach of said codingrelays for'imparting a slow drop-out characteristicthereto means effective in response to pick-upof said control relay forenergizing the winding of one of said coding relays to cause pick-upthereof, means eifective in response to pick-up of said one coding relayto cause energization of the winding of the other coding relay to causepick-up thereof, means effective in response to-pick-up of said othercoding relay for effecting deenergization of the winding of said onecoding relay, said coding relays being thereby alternatelypicked-up anddropped-out as long as said control relay is picked-up, in such a manneras to causesaid one coding-relay to be dropped-out while said-othercoding relay is picked-up -for a certain length of time 'corres'pondm tothe dro out time of said other coding relay and to cause said two codingrelays to be simultaneously picked-up for a certain length or timecorresponding to the drop-out time of said one coding relay, meanscontrolled jointly *bys'a'id two coding relays for effecting periodiccontrol impulses, and timing means set in operation in response topick-up of said control relay to effect deenei'g'i'zation of the windingof said control relay and the consequent restoration thereof to itsdropped-out position at the expiration of a certain length of timefollowing the .pi'ok up of the relay, whereby to terminate the operationof said coding relays and the consequent periodic control impulse.

6. In a control system, the c'orn'binationof two selectively operablecontrol devices, a pair *0! coding relays, means effective in responseto operation of one of said control devices for causing continuedalternate pick-up and drop-out of sold coding relays, means controlledJointly bysaid coding relays for producing a periodic control impulsewhile said coding relays are "alternately picked-up and 'drop'ped out,and means responsive to the operation of the other of said controldevices for causing continuous pick-up of only a certain one of saidcoding relays, said two coding relays being :iointly eifective whilesaid one certaincoding relay is pioked up for-eiledting a continuouscontrol impulse.

'7. In a control system, the combination of two selectively operablecontrol "devices, a pair or coding relays, means effective in responseto operation of one of said control devices i'o'r causing continuedalternate ipi'c'kmp and drop-out -of s'a'id coding relays, mea-nscontrolled jointly by said coding relays for producing a periodiccontrol impulse while said coding relays are alternately picked-"up anddroppedwut, means responsive to the operation of the other o'f said-control devices for causing continuous apick-up or "only one certainone of said coding relays, said two coding relays being jointly'efiective while saidbne certain coding relay is ipicked up =fo'r:produ'c-mg a continuous control impulse, and timing -means-set inoperation in response to the operation-of-cither of said control devicesand effective at the expirationbf a certain length of time following theoperation thereof for-causing both of said coding relays to be restored-to their dropped-out positions whereby to terminate the production otany control impulse.

CLAUDE M.

No references cited.

